1. Field of the Invention
The present invention relates to flameproofed, impact-modified, scratch-resistant polycarbonate (PC) compositions and moulding compositions with surface-modified, calcined kaolin as filler, which have good mechanical properties, good flowability and high chemical resistance, a process for the production thereof and their use for the production of mouldings.
2. Description of Related Art
US 2007/0072960 A1 describes flameproofed thermoplastic compositions containing polycarbonate, a polycarbonate-polysiloxane copolymer (SiCoPC) and a filler silanised by surface treatment (e.g. talc, clay, wollastonite, silica, glass, quartz or mica treated with vinyl silane), which can additionally contain an impact modifier.
In EP 758003 A2, polycarbonate compositions are described with improved surface properties and a high modulus, which contain an inorganic filler and phosphoric acid ester as flame retardant. Glass fibres, carbon fibres, talc, clay or mica are mentioned as inorganic fillers; calcined kaolin and the addition of an impact modifier, on the other hand, are not described.
WO 2003082965 discloses flameproofed polymer compositions containing a polymer and a particulate clay mineral, wherein the particle count is at least 1 per 100 cubic micrometres and the clay mineral is not organomontmorillonite. Kaolin, partially calcined and fully calcined kaolin are specifically claimed. In contrast to the present invention, however, surface-modified calcined kaolins are not described.
EP 525955 A1 describes flameproofed polymer compositions comprising a polycarbonate blend or polyester carbonate blend and a filler treated with liquid polydiorganosiloxane (e.g. calcined kaolin). In EP 525955 A1, neither phosphorus-containing flame retardants nor impact modifiers are described.
EP 707978 A1 describes a recording material which contains, inter alia, a protective layer with optionally surface-modified calcined clay dispersed in a binder (PC) on a support. However, the compositions are neither impact-modified nor flameproofed.
From WO 1982002398 A1, thermoplastic polycarbonate compositions are known which contain a silane-modified filler, e.g. a kaolin. As in EP 707978 A1, however, neither impact-modified nor flameproofed compositions are described.
EP 66772 A2 describes a polycarbonate composition consisting of an aromatic thermoplastic PC and 0.025-5 parts by weight of a silicate with an average particle size of 0.05-20 micrometres. The addition of impact modifiers and flame retardants, on the other hand, is not described.